Vacuum mandrel



E. A. LINK VACUUM MANDREL 'Nov. 20, 1951 Original Filed Oct. 21, 1947INVENTOR. 6% j [/22 BY m fir jg/ ZZZ Patented Nov. 20, 1951UNITED-STATES PATENT OFFICE VACUUM MANDREL Edwin A. Link, Milwaukee,Wis., assignor to Me- Graw Electric Company, Milwaukee, Wis., acorporation of Delaware 1 Claim. 1

This invention relates to vacuum mandrels.

This application is a division of my prior application Serial No.781,073, filed October 21, 1947, now Patent No. 2,567,387 datedSeptember 11, 1951, for Vacuum Mandrels, assigned to the same assigneeas the present application In making capacitors, long ribbons of metalfoil and dielectric are wound into a cylindrical form and are thenusually flattened. These ribbons are delicate and easily injured and ithas been found difiicult to start the Winding and hold the ribbons tothe mandrel and to remove the wound assembly without damage to theribbons.

This invention is designed to overcome the above noted difiiculties andobjects of this invention are to provide a novel form of vacuum mandrelwhich will hold the ribbons to the mandrel and insure compact anduniform winding and which will provide means for readily detaching andfreeing the wound assembly from the mandrel so that it may be freelyslipped from the mandrel without any injury to the ribbons although themandrel is not tapered but is a true cylinder throughout.

An embodiment of the invention is shown in the accompanying drawings, inwhich:

Figure l is a longitudinal sectional view showing the mandrel, such viewbeing partly broken away.

Figure 2 is a side view of the structure shown in Figure 1 on a reducedscale and showing the manner in which the mandrel is connected to thethree-way valve.

Referring to the drawings, it will be seen that a support or plate I isprovided with a bearing supporting casing 20 on its rear side andrevolubly carries the shaft 2|, preferably ball bearings 22 and 23 beingprovided, at spaced points on the shaft 2| so as to secure the shaftagainst lateral motion. The shaft rigidly carries the mandrel 24. Forinstance, the mandrel may be screwed onto the outer end of the shaft 2|as shown in Figure 1 and may have a snug fit with the shaft at its innerend. The mandrel is provided with a plurality of apertures 25 and theshaft is provided with a passageway 26 communicating with the hollowinterior of the mandrel and consequently with the apertures 25. Theshaft 2| is connected by means of a rotary air coupling 21 with a pipe28. This pipe is connected with the three-way valve I1 by means of aflexible hose or tubing 29 so that any jarring or slight motion of thepipe 28 will not be communicated to the three-way valve 17. The mandrelis rotated in any suitable manner as by means of the worm wheel 3!]driven by the worm 3 l.

A three-way valve l! is arranged to selectively connect the pipe 29 andconsequently the hollow interior of the mandrel with a source of vacuumas by means of the vacuum pipe I8 or with a source of compressed air asby means of the compressed air pipe 19.

In using the apparatus the three-way valve is turned so as to connectthe hollow interior of the mandrel with the vacuum source and thusproduce a suction at each of the openings 25. The outermost sheet ofdielectric ribbon is brought into contact with the mandrel and themandrel is rotated. This sheet 'is held by suction to the mandrel and iswound thereon and the other sheets of dielectric ribbon and foil ribbonare led into the space between the first sheet and its partially woundportion. The winding is continued until the requisite number of layershas been formed. The sheets are held tightly to the mandrel and areundamaged.

When a sufficient number of layers has been formed the mandrel isstopped, the sheets cut across, and the three-Way valve is turned toadmit compressed air. This forces a minute film of air between the Woundassembly and the mandrel and allows the assembly to be readily slippedoff the mandrel.

It will be seen that a novel form of vacuum mandrel has been provided bythis invention which is particularly useful in the winding of thedelicate dielectric and foil ribbons of capacitors.

It is to be noted particularly that there is no danger of damaging thesedelicate ribbons during the winding process or during the removalprocess.

Although this invention has been described in considerable detail, it isto be understood that such description is intended as illustrativerather than limiting, a the invention may be variously embodied and isto be interpreted as claimed.

I claim:

A vacuum mandrel construction comprising a support, a shaft revolublysupported from said support and having an inner end portion and anoutwardly projecting portion, bearing means between said support andsaid shaft arranged to provide axially spaced bearing zones for saidshaft, means for rotating said shaft, a mandrel rigidly carried by theoutwardly projecting portion of said shaft and having substantiallyairtight connection with said shaft at the inner and outer ends of saidmandrel, said mandrel having a plurality of apertures opening throughits peripheral surface, said shaft having a passageway opening throughits inner end portion and communicating with the aperture in saidmandrel, a source of vacuum, a source of compressed air, valve means,and a rotary air coupling between the inner end portion of said shaftand said valve means, said valve means being arranged to selectivelyconnect the passageway of said shaft with said source of vacuum and saidsource of compressed air.

EDWIN A. LINK.

No references cited.

